1. Field of the Invention
The present invention relates to a temperature-compensator of a torque sensor which detects a torque on the basis of each inductance change of a pair of coils.
2. Description of the Related Art
In the torque sensor, the coil itself has temperature characteristics and changes in the temperature due to thermal expansion of a component of the torque sensor. For example, its entire housing or the like affect torque detection output thereby disturbing detection of an accurate torque.
Thus, the torque sensor is provided with a temperature sensor dedicated for detecting the temperature of the same torque sensor such as a thermister so as to correct the value of a detected torque according to a detected temperature of the temperature sensor.
The thermister needs to be provided on the torque sensor so as to detect the temperature thereof with an excellent sensibility for the temperature. Therefore, a substrate or a holding component for holding the thermister is required, so that the quantity of required components increases leading to an increase of cost.
The present invention has been achieved in views of those problems. An object of the present invention is to provide a temperature-compensating device capable of compensating for the temperature of a torque sensor without use of any temperature sensor dedicated for temperature detection, wherein reduction of cost can be achieved by reducing the quantity of required parts.
According to the present invention, there is disclosed a temperature-compensating device of a torque sensor including a pair of coils in which inductance change in opposite directions corresponding to torque and a torque detecting means for outputting torque detection voltages from first and second voltages based on a change in inductance of each of the pair of the coils. The torque detecting means contains an adding means for adding the first voltage to the second voltage and outputting as a temperature detection voltage. The torque detecting means contains a memory means for memorizing temperature characteristics of the temperature detection voltage of the adding means preliminarily measured. The torque detecting means also contains a correcting means for correcting the torque detection voltage with a temperature detected from the temperature detection voltage outputted by the adding means according to the temperature characteristics.